Light emitting element, light source device, and projection display device

Abstract

The present invention includes light source layer (4) and directivity controlling layer (5) into which light emitted from light source layer (4) enters. Light source layer (4) has a pair of hole transport layer (11) and electron transport layer (13) formed on substrate (10). Directivity controlling layer (5) has plasmon excitation layer (15) that is laminated on non-substrate (10) side of light source layer (4) and that has a higher plasma frequency than light emitted from light source layer (4) and wave number vector conversion layer (17) that converts surface plasmons that are generated in plasmon excitation layer (15) into light having a predetermined emission angle and emits the light having the predetermined emission angle. Plasmon excitation layer (15) is sandwiched between two layers having dielectricity. The effective dielectric constant of the incident side portion including the entire structure laminated on light source layer (4) side of plasmon excitation layer (15) is greater than that of the emission side portion including the entire structure laminated on wave number vector conversion layer (17) side of plasmon excitation layer (15) and a medium that contacts wave number vector conversion layer (17).

Description

TECHNICAL FIELD[0001]The present invention relates to a light emitting element, a light source device, and a projection display device that use surface plasmons to emit light.BACKGROUND ART[0002]An LED projector that uses a light emitting diode (LED) as a light emitting element for a light source has been proposed. The LED projector of this type has an illumination optical system into which light emitted from the LED enters; a light valve having a liquid crystal display panel into which light emitted from the illumination optical system enters and a DMD (Digital Micromirror Device); and a projection optical system that projects light emitted from the light valve to a projection plane.[0003]A requirement for the LED projector is that be a minimum of optical loss in the optical path from the LED to the light valve so as to improve the luminance of projected images.[0004]In addition, as described in Non-Patent Literature 1, the LED projector is restricted by the etendue that depends on...

AI Technical Summary

Benefits of technology

The present invention provides a light emitting element that can improve both luminance and directivity of emission light. The light emitting element includes a light source layer and an optical element layer that converts surface plasmons into light having a predetermined exit angle. The effective dielectric constant of the incident side portion is greater than that of the emission side portion. The light source device and the projection display device that use this light emitting element have high luminance and high directivity.

Problems solved by technology

Although this structure can achieve high luminance, it cannot narrow the emission angle of light that is emitted from the light emitting element to less than ±15°.

In other words, the light emitting element described in Patent Literature 1 has a drawback in which the directivity of emission light is low.

Thus, there is a problem in which, even if the light emitting element described in Patent Literature 2 is applied to an LED projector, sufficient luminance can not be obtained.

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